By: Carey GoldbergRepublished by wbur. View the article at the wbur website here.

New MIT research finds that for children's brain development, parents don't just need to talk to their kids — it's important to talk with them, in back-and-forth exchanges.

"What we found is, the more often parents engaged in back-and-forth conversation with their child, the stronger was the brain response in the front of the brain to language," said cognitive neuroscience professor John Gabrieli.

That stronger brain response, measured as children ages 4 to 6 lay in a scanner listening to simple stories, reflects a deeper, more intimate engagement with language, said graduate student Rachel Romeo.

On average, a child from a better-off, more-educated family is likely to hear 30 million more words in the first three years of life than a child from a less-well-off family.

That finding from 1995 helped explain some school achievement gaps. Now, the MIT researchers have illuminated how more talking actually changes a child's brain — and it's not just about the number of words a child hears, Romeo said. It's about interaction, the number of conversational "turns" that parents and preschool-aged children took while wearing recorders that taped their every word over two days.

And the effect didn't depend on parents' income or education, she noted, so it's not as if lower-income children are "doomed" to weaker verbal abilities.

"It seems to suggest, instead, that if they're provided with a rich verbal environment early in life, that that can predict great language and cognitive outcomes," Romeo said.

The finding is an important addition to work over the last 20-plus years on language development, said Dr. Marilyn Augustyn, a behavioral pediatrician at Boston Medical Center who was not involved in the study. She praised its use of brain scanners and recording devices to move the research forward.

A previous study turned up similar MRI findings on children who were read to by their parents, she said, "But what's really revolutionary about this study — and why I think it's really important — is it did both: It looked at the conversations, the words that children heard, and then also looked at the brain activation."

It strengthens a two-part message, she added. "One, we need to talk to our children from the moment they're born, and probably in utero. And two, that language needs to come out of a relationship — and that's what this study really cements. It isn't about streaming tape to a child through the course of a day with thousands and thousands of words, because those become meaningless. It's really about the relationship."

The next step in the research, Romeo said, will be to study an early intervention that gives toddlers more back-and-forth conversations.

"Obviously a two-year-old is not going to debate philosophy with you, but just a back and forth with them, whatever their capabilities are, is really valuable," she said.

The study found a broad range in how many conversational "turns" parents and child took in the course of an hour, from just 90 to as many as 400, Romeo said.

Families under more stress — say, with parents holding down more jobs — may have a harder time changing their conversational interactions with children, Gabrieli acknowledged. "But it is a thing — a very specific thing — that any of us could do with the right encouragement and support," he said.

Passively watched screens clearly do not bring the same sort of interaction as real conversation. But could a smart speaker use artificial intelligence to develop a child's brain much as a conversational parent would?

That question will require more study, the researchers said. Some initial research suggests that if devices can really respond to what a child says, they may offer added benefits, Romeo said.

But Dr. Augustyn is skeptical. Children can become very connected to technology, she said, but even if they develop some sort of relationship with a smart speaker, ultimately, "Alexa doesn't have a lap."